使用消毒劑消毒水源是為了消滅水中致病菌，但使用消毒劑卻會無預期地產生對人體健康有害的副產物，而其中一種具毒性的消毒副產物，二甲胺亞硝基(N-nitrosodimethylamine，簡稱NDMA)增加了致癌風險，因此水中的NDMA是目前大眾關心的新興議題，NDMA已被US-EPA歸類為非常規性的汙染物(UCMR-2)，但尚未制定明確的限制含量。 在本篇研究中，發展一套簡便的樣品前處理方法，分散微固相萃取法(Dispersive Micro Solid Phase Extraction，簡稱dMSPE)，利用此方法萃取水樣因氯消毒而產生的NDMA，以及不同碳鏈的亞硝胺類化合物，再結合氣相層析質譜儀做為檢測工具。 本研究探討了影響dMSPE萃取效率的參數並將其最佳化。最佳化實驗萃取條件是使用商業化的碳分子篩－Carboxen 1003，加入其75 mg於含氯化鈉至5% 的50 mL水樣中，搖盪20分鐘完成萃取後，快速過濾吸附劑後以150 μL的二氯甲烷回溶。萃取完成後直接取10 μL以直接進樣裝置導入氣相層析質儀，以化學游離法和選擇離子儲存模式進行分析，可測得亞硝胺的定量極限小於0.9 ng/L。在真實水樣的應用中，可測得室內/外游泳池水中含有NDMA，濃度介於4.7－127.4 ng/L間，萃取回收率在57－114%間，相對標準偏差小於20%。本研究發展的dMSPE是個簡便並且使用微量有機溶劑的前處理技術，即可有效的萃取水樣中的NDM即其它亞硝胺類。 Abstract Disinfection has successfully applied to eliminate pathogens in various water supplies, however its byproducts (DBPs) cause unintended health risks to human. N-nitrosodimethylamine (NDMA) is one of the most toxic DBPs that raises the cancer risk. Due to its high toxicity, nowadays, the presence of NDMA and other N-nitrosamines in water is an emerging issue since many of them are suspected to be human carcinogens. They are also listed in the Unregulated Contaminant Monitoring Rule 2 (UCMR-2) by US-EPA. In this study, a simple sample pretreatment technique, dispersive micro-solid phase extraction (dMSPE), was developed for the extraction of NDMA and other N-nitrosamines (NAs) from aqueous samples. The parameters affecting the extraction efficiency were systematically investigated and the conditions optimized. The best extraction conditions involved the immersed 75 mg of carbon molecular sieve, carboxen 1003 (as adsorbent), in a 50 mL water sample containing 5% of sodium chloride in a sample tube. After 20 min of shaking extraction, the adsorbent was collected under rapidly filtered, and 150 ?L of dichloromethane was used to elute NAs from the adsorbent. The extract 10 ?L was then directly determined by large-volume injection gas chromatography with chemical ionization mass spectrometry (GC-CI/MS) under selected ion storage mode. The limits of quantitation (LOQs) were less than 0.9 ng/L. The method was validated through a recovery study of various environmental III samples. Concentrations of NDMA in swimming pool water samples were detected ranging 4.7 to 127.4 ng/L, and recovery ranged from 57-113% and the relative standard deviation was below 20%. This developed method is a simple and solvent-less pretreatment method to detect NDMA and other N-nitrosamines in aqueous sample.
